4Kbit I2C EEPROM for configuration storage
The Microchip AT24C04D-SSHM-B is a 4Kbit serial EEPROM organized as 512 x 8 bits, accessed through an I2C interface running up to 1 MHz. It stores firmware parameters, calibration data, or device configuration in a non-volatile memory block that retains data without power. The 450 ns access time supports back-to-back reads at full bus speed without wait states.
Faster access than the C-suffix siblings
The D-suffix parts spec a 450 ns access time, compared to 550 ns on the AT24C04C variants. That 100 ns margin matters when the I2C bus is heavily loaded or the master's setup/hold budget is tight at 1 MHz. The AT24CSW040-STUM-T also runs 450 ns, so it's a speed peer but in a different package footprint. If you're swapping a C-suffix part into an existing layout, the D-suffix drops in pin-compatible — same 8-SOIC, same I2C address map.
Active production, no end-of-life watch needed
The base product number AT24C04 spans multiple generations — the D-suffix is the current mainstream offering from Microchip.
Industrial temp, surface-mount assembly
The 8-SOIC package with 1.27 mm pitch is a standard footprint — no exotic land pattern. Bulk tube shipping means it's intended for hand-load or low-volume production; if you need reel for automated pick-and-place, the AT24C04C-XHM-T is the tape-and-reel equivalent with a slightly slower access time.